Sound absorbing cell and sound absorbing structure having the same

Abstract

A sound absorbing cell according to an exemplary embodiment of the present invention is formed of a plurality of plates that are stacked while interposing an air layer therebetween, wherein the plurality of plates include: a reflective plate that is disposed outermost from a space where sound is generated; and a microperforated plate that is stacked on the reflective plate and having a plurality of holes perforated therein.

What is claimed is: 
     
       1. A sound absorbing cell formed of a plurality of plates that are stacked while interposing an air layer therebetween, wherein the plurality of plates comprise:
   a reflective plate disposed outermost from a space where sound is generated;   a first microperforated plate stacked on the reflective plate and having a first plurality of holes perforated therein;   a first elastic plate stacked on the first microperforated plate;   a second microperforated plate stacked on the first elastic plate and having a second plurality of holes perforated therein; and   a second elastic plate stacked on the second microperforated plate,   
 wherein the first and second elastic plates have a different thickness from each other, 
 wherein the first and second microperforated plates have a different thickness from each other, and 
 wherein the first and second microperforated plates have a different perforation ratio from each other. 
 
     
     
       2. The sound absorbing cell of  claim 1 , wherein the first and second microperforated plates are elastic. 
     
     
       3. The sound absorbing cell of  claim 1 , wherein each of the first elastic plate, second elastic plate, first microperforated plate, and second microperforated plate has a thickness of 1 mm or less. 
     
     
       4. The sound absorbing cell of  claim 1 , wherein a diameter of each hole of the plurality of holes perforated in the first and second microperforated plates is 1 mm or less. 
     
     
       5. The sound absorbing cell of  claim 1 , wherein perforation ratios of the first and second microperforated plates are 1% or less. 
     
     
       6. A sound absorbing structure comprises:
 a plurality of sub-cells; and 
 a plurality of barrier ribs provided between adjacent sub-cells of the plurality of sub-cells to partition off the plurality of sub-cells from the sound absorbing structure, 
 wherein each of the plurality of sub-cells is formed of a plurality of plates that are stacked while interposing an air layer therebetween, and 
 wherein the plurality of plates comprise:
 a reflective plate disposed outermost from a space where sound is generated; 
 a first microperforated plate stacked on the reflective plate and having a first plurality of holes perforated therein; 
 a first elastic plate stacked on the first microperforated plate; 
 a second microperforated plate stacked on the first elastic plate and having a second plurality of holes perforated therein; and 
 a second elastic plate stacked on the second microperforated plate, 
 
 wherein the first and second elastic plates have a different thickness from each other, 
 wherein the first and second microperforated plates have a different thickness from each other, 
 wherein the first and second microperforated plates have a different perforation ratio from each other, and 
 wherein the plurality of sub-cells have a different sound absorbing frequency band from each other. 
 
     
     
       7. The sound absorbing structure of  claim 6 , wherein at least one sub-cell of the plurality of sub-cells comprises different numbers of plates from the other sub-cells of the plurality of sub-cells. 
     
     
       8. The sound absorbing structure of  claim 6 , wherein at least one sub-cell of the plurality of sub-cells has a different thickness of the one sub-cell from the other sub-cells of the plurality of sub-cells. 
     
     
       9. The sound absorbing structure of  claim 6 , wherein at least one sub-cell of the plurality of sub-cells has different area size from the other sub-cells of the plurality of sub-cells. 
     
     
       10. The sound absorbing structure of  claim 6 , wherein when viewed from a front, each of the sub-cells has a rectangular shape, and the plurality of sub-cells are arranged while contacting a side of the rectangular shape between neighboring sub-cells. 
     
     
       11. The sound absorbing structure of  claim 6 , further comprises:
 a frame provided at an outer edge of the sound absorbing cell, 
 wherein the plurality of barrier ribs is provided between neighboring sound absorbing cells in the frame.